Rotary machines, including turbines are widely used in a variety of aviation, industrial, and power generation applications to perform work. Each rotating machine generally includes alternating stages of peripherally mounted stator vanes and rotating blades. The stator vanes may be attached to a stationary component such as a casing that surrounds the rotating machine, and the rotating blades may be attached to a rotor located along an axial centerline of the rotating machine. A compressed working fluid, such as but not limited to steam, combustion gases, or air, flows along a gas path through the rotating machine to produce work. The stator vanes accelerate and direct the compressed working fluid onto the subsequent stage of rotating blades to impart motion to the rotating blades, thus turning the rotor and performing work.
Compressed working fluid that leaks around or bypasses the stator vanes or rotating blades reduces the efficiency of the rotating machine. As a result, the casing surrounding the turbine often includes a stationary shroud or stationary shroud segments that surround and define the outer perimeter of the gas path to reduce the amount of compressed working fluid that bypasses the stator vanes or rotating blades. In addition, each rotating blade may include a tip shroud disposed at an outer radial tip of the rotating blades. As the turbine rotates and cycles through various stages of operation, the tip shrouds may form a seal at the radial tip of the turbine blades and further reduce leakage of the compressed working fluid between the radial tip of the blade and the casing.
Tip shroud aerodynamic properties and mechanical performance are important design considerations that balance efficiency and performance on the one hand with blade life on the other hand. For example, although a tip shroud may reduce leakage of the working fluid, tip shrouds also generally increase the mass at the tip of the blade, which may increase creep or yield of the tip shroud. Creep or yield, in turn may reduce the life of the turbine blade, increase maintenance cost and/or extend outages. In addition, a tip shroud that fails may introduce debris into the gas path that may cause significant damage to the casing, downstream stators, and/or blades. As a result, continued improvements in devices and methods for aligning tip shrouds in a rotary machine would be useful.